فإن الكتاب أود أن أشكر الدكتور هونغ يي في جامعة إيموري الأساسية المتكاملة للتصوير المجهري المجهر الإلكتروني. وقد رعت هذا العمل من قبل المعاهد الوطنية للصحة منح (PN2EY018244، R01 CA108468، U54CA119338، و1K99CA154006 01-).

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Health Part A. 47, 267-283 (1996).</li></ol>

الإعلان عن أي تضارب في المصالح.

مقارنة التقليدية نقاط الكم CdSe، يمكن ضبطها الثلاثي سبائك الزئبق أسطوانة 1-X البلورات النانوية سي في الحجم والطول الموجي مضان بشكل مستقل. يتم تحديد حجم أولا خلال تجميع النوى النانوية CdSe، ويتم اختيار الطول الموجي مضان في خطوة الزئبق الثانوية تبادل الأيونات الموجب...

<table border="1" style=";text-align:right;direction:rtl"><tbody><tr><td> اسم كاشف </td><td> شركة </td><td> كتالوج رقم </td><td> التعليقات (اختياري) </td></tr><tr><td> عنصر السيلينيوم </td><td> سيغما الدريخ </td><td> 229865 </td><td></td></tr><tr><td> ثلاثي N-octylphosphine </td><td> Strem </td><td> 15-6655 </td><td> 97٪ نقية، وغير مستقرة في الهواء </td></tr><tr><td> الكادميوم أكسيد </td><td> سيغما الدريخ </td><td> 202894 </td><td> شديدة السمية: توخي الحذر </td></tr><tr><td> Tetradecylphosphonic حمض </td><td> PCI التجميعي </td><td> 4671-75-4 </td><td></td></tr><tr><td> Octadecene </td><td> الفا Aesar </td><td> L11004 </td><td> التقنية الصف </td></tr><tr><td> Hexadecylamine </td><td> سيغما الدريخ </td><td> H7408 </td><td></td></tr><tr><td> Diphenylphosphine </td><td> سيغما الدريخ </td><td> 252964 </td&gt; <td> التلقائية الاشتعال </td></tr><tr><td> الزئبق خلات </td><td> سيغما الدريخ </td><td> 456012 </td><td> شديدة السمية: توخي الحذر </td></tr><tr><td> 1-Octanethiol </td><td> سيغما الدريخ </td><td> 471836 </td><td> رائحة قوية </td></tr><tr><td> حمض الأولييك </td><td> سيغما الدريخ </td><td> W281506 </td><td></td></tr><tr><td> الزنك خلات </td><td> الفا Aesar </td><td> 35792 </td><td></td></tr><tr><td> الكادميوم هيدرات خلات </td><td> سيغما الدريخ </td><td> 229490 </td><td> شديدة السمية: توخي الحذر </td></tr><tr><td> Oleylamine </td><td> فيشر العلمية </td><td> AC12954 </td><td> غير مستقرة في الهواء </td></tr><tr><td> كبريت </td><td> سيغما الدريخ </td><td> 344621 </td><td></td></tr><tr><td> Trioctylphosphine أكسيد </td><td> Strem </td><td> 15-6661 </td><td> 99٪ </td></tr><tr><td> بيريدين </td><td> VWR </td><td> EM-PX2012-6 </td><td> لا مائي </td></tr><tr><td> Thioglycerol </td><td> سيغما الدريخ </td><td> M1753 </td><td> رائحة قوية </td></tr><tr><td> الترايثلامين </td><td> سيغما الدريخ </td><td> 471283 </td><td> لا مائي </td></tr><tr><td> غسيل الكلى أنابيب </td><td> الطيف مختبرات </td><td> 131342 </td><td> 20 كيلو دالتون قطع </td></tr><tr><td> الطرد المركزي فلتر </td><td> ميليبور </td><td> UFC801024 </td><td> قطع 10 كيلو دالتون </td></tr><tr><td> Monoamino-PEG </td><td> راب Polymere </td><td> 12 750-2 </td><td> 750 دا </td></tr><tr><td> DMTMM، 4 - (4،6-Dimethoxy-1 ،3،5-triazin-2-YL)-4-methylmorpholinium هيدرات كلوريد </td><td> الفا Aesar </td><td> H26333 </td><td></td></tr><tr><td> AKTAprime زائد اللوني النظام </td><td> GE للرعاية الصحية </td><td></td><td></td></tr><tr><td> Superose 6 10/300 العمود اللوني GL </td><td> GE للرعاية الصحية </td><td> 17-5172-01 </td><td></td></tr><tr><td> الاغاروز، OmniPur </td><td> VWR </td><td> EM-2120 </td><td></td></tr><tr><td></td><td></td><td></td><td> ملحق توليف octanethiolate الزئبق: إضافة ببطء حل الميثانول من خلات الزئبق (1 مكافئ.) إلى حل من اثارة octanethiol-1 (3 مكافئ.) وهيدروكسيد البوتاسيوم (3 مكافئ.) في الميثانول في درجة حرارة الغرفة. عزل الراسب الزئبق octanethiolate (II) عن طريق الترشيح، وغسل مرتين ومرة ​​واحدة مع الميثانول مع الأثير، وجاف ثم تحت الفراغ. توليف البوليمر متعدد الأسنان: حل حامض polyacrylic (1 غرام، 1773 دا) في ثنائي ميثيل فورماميد مل 25 (DMF) في قارورة 150 مل ثلاث العنق وفقاعة مع الأرجون لمدة 30 دقيقة. إضافة إلى حل اللامائية من cysteamine (374 ملغ و 4.87 ملمول) في DMF 10 مل. في درجة حرارة الغرفة مع التحريك القوي، إضافة ببطء diisopropylcarbodiimide اللامائية (مدينة دبي للإنترنت، 736 ملغ، 5،83 ملمول) أكثر من 30 دقيقة، تليها الترايثلامين (170 ميكرولتر، 1.22 ملمول)، والسماح للرد فعل على المضي قدما لمدة 72 ساعة في 60 ° C. إضافة المركابتويثانول (501 ملغ، 6،41 ملمول) لإرواء رد الفعل، ويقلب لمدة 2 ساعة في درجة حرارة الغرفة. إزالة DMF عبر التبخر الدوارة وعزل البوليمر مع إضافة مزيج من الجليد 02:01 الباردة الأسيتون: كلوروفورم، تليها الطرد المركزي. حل البوليمر في ~ 5 DMF اللامائية مل والتصفية ويعجل مرة أخرى مع ايثر، وتكرار. تجفيف المنتجات تحت التفريغ وتخزين تحت الأرجون. تحديد قطرها الأساسية CdSe: من طيف الامتصاص للأشعة فوق البنفسجية فيس تحديد الطول الموجي للذروة exciton الأول (λ، في نيو مكسيكو)، والذي هو ذروة أطول الطول الموجي (على سبيل المثال ما يقرب من 498 نانومتر لCdSe في الشكل 2A)، واستخدام التحجيم منحنى مولفاني وزملاء العمل 12: <img src="/files/ftp_upload/4236/4236eq1.jpg" alt= &quot;المعادلة 1&quot; /&gt; تحديد تركيز النانوية CdSe: من خلفية طرح-UV-الطيف فيس من حل واضح بصريا من البلورات النانوية CdSe، وتحديد الطول الموجي في امتصاص نانومتر 350. ويمكن استخدام التخفيفات المسلسل لتحديد ما إذا كان هو امتصاص البصرية ضمن نطاق خطية من قانون بير. يمكن تحديد تركيز النانوية (QD، في M) عن طريق توصيل في قطر النانوية (D، في نيو مكسيكو)، وقيمة الامتصاص الضوئي (A 3SA)، وطول الطريق كوفيت (ل، في سم) في المعادلة التالية من العلاقة التجريبية من Bawendi وزملاء العمل 13: <img src="/files/ftp_upload/4236/4236eq2.jpg" alt="المعادلة 2" /></td></tr></tbody></table>

compact quantum dots for single-molecule imaging

واحدة جزيء التصوير أداة مهمة لفهم آليات وظيفة الجزيئية البيولوجية والرؤية وعدم التجانس المكاني والزماني من السلوكيات الجزيئي التي تكمن وراء البيولوجيا الخلوية 1-4. الصورة لجزيء الفردية للمصلحة، فمن عادة مترافق إلى علامة فلوري (صباغة، البروتين، وحبة، أو الكم نقطة)، ولاحظ مع epifluorescence أو الكلي المجهر التأمل الداخلي (TIRF) مضان. بينما الأصباغ والبروتينات الفلورية كانت الدعامة الأساسية لمضان التصوير على مدى عقود، من مضان غير مستقر في ظل تدفقات عالية الفوتون اللازمة لمراقبة الجزيئات الفردية، مما أسفر سوى بضع ثوان للمراقبة قبل فقدان كامل للإشارة. حبات الخرز والمطاط صبغ المسمى توفير الاستقرار تحسنت إشارة لكن على حساب حجم أكبر بشكل كبير الهيدروديناميكية التي يمكن أن تغير deleteriously نشر وسلوك جزيء قيد الدراسة ntent &quot;&gt; نقاط الكم (QDs) توفر التوازن بين هذين النظامين للمشاكل. وتتكون هذه الجسيمات النانوية من المواد أشباه الموصلات ويمكن هندستها مع الحجم الصغير مع المقاومة hydrodynamically استثنائية للتحلل الضوئي 5. وهكذا في السنوات الأخيرة كان لها دور أساسي QDs في تمكين على المدى الطويل مراقبة سلوك الجزيئات المعقدة على مستوى جزيء واحد، ولكن ما زالت هذه الجسيمات تم العثور لعرض ضعف الانتشار في البيئات المزدحمة مثل الجزيئية السيتوبلازم الخلوي ومتشابك الخلايا العصبية الحلقي، حيث لا تزال أحجامها كبيرة جدا 4،6 ، 7. ونحن مؤخرا المهندسة والنوى والطلاء سطح QDs لحجم مصغر الهيدروديناميكية، في حين تحقيق التوازن بين إزاحة للاستقرار الغروية، صمود للضوء، والسطوع، وملزم غير محددة التي أعاقت فائدة QDs المضغوط في 8،9 الماضية. الهدف من هذه المقالة هو لإثباتتركيب، وتعديل، وتوصيف هذه البلورات النانوية الأمثل، يتكون من قرص مضغوط سبائك الزئبق X 1-X سي الأساسية المغلفة مع الزنك العازلة ذ CD 1-Y قذيفة S، المزيد المغلفة مع يجند البوليمر تعديل متعدد الأسنان مع البولي ايثيلين جلايكول قصيرة ( PEG) سلاسل (الشكل 1). مقارنة مع البلورات النانوية CdSe التقليدية، الزئبق أسطوانة 1-X سبائك سي تتيح قدرا أكبر من عائدات الكم من مضان، مضان في الأطوال الموجية الحمراء وتحت الحمراء القريبة لتعزيز إشارة الضوضاء لفي الخلايا، والإثارة في غير السامة للخلايا موجات مرئية. متعدد الأسنان الطلاء البوليمر ربط سطح النانوية في التشكل مغلقة ومسطحة لتقليل حجم الهيدروديناميكية، وPEG يحيد التهمة سطح ملزمة للحد من غير محدد إلى الخلايا والجزيئات الحيوية. والنتيجة النهائية هي النانوية مع نيون الزاهية الانبعاثات بين 550-800 نانومتر وحجم إجمالي الهيدروديناميكية بالقرب 12 ميل بحري. هذا هو في لياليمجموعة AME حجم والعديد من البروتينات الكروية قابلة للذوبان في الخلايا، وأصغر بكثير من مضاد للفيروسات التقليدية QDs (25-35 نانومتر).

يصور الشكل 2 امتصاص الأطياف وممثل عن البلورات النانوية مضان CdSe، الزئبق أسطوانة 1-X البلورات النانوية سي بعد تبادل الأيونات الموجبة، والزئبق أسطوانة 1-X SE / مؤتمر نزع السلاح Y Y الزنك 1-S البلورات النانوية بعد نمو القواقع. والبلورات النانو?...

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Compact Quantum Dots for Single-molecule Imaging

وصفنا إعداد نقاط الكم الغروية مع حجم مصغر لتصوير الهيدروديناميكية مضان واحدة جزيء. مقارنة نقاط الكم التقليدية، هذه الجسيمات النانوية هي مماثلة في الحجم إلى البروتينات الكروية وهي الأمثل لواحدة جزيء السطوع والاستقرار ضد التحلل الضوئي، ومقاومة غير محددة ملزمة للبروتينات وخلايا.

الكم النقاط المدمجة لواحدة جزيء التصوير

Single-molecule imaging is an important tool for  understanding the mechanisms of biomolecular function and for visualizing the  spatial and temporal ...

compact-quantum-dots-for-single-molecule-imaging

Research

JoVE Journal

Engineering

18.0K Views.  Emory University. وصفنا إعداد نقاط الكم الغروية مع حجم مصغر لتصوير الهيدروديناميكية مضان واحدة جزيء. مقارنة نقاط الكم التقليدية، هذه الجسيمات النانوية هي مماثلة في الحجم إلى البروتينات الكروية وهي الأمثل لواحدة جزيء السطوع والاستقرار ضد التحلل الضوئي، ومقاومة غير محددة ملزمة ?...

Video: Compact Quantum Dots for Single-molecule Imaging

Gradient Echo Quantum Memory in Warm Atomic Vapor

Gradient echo memory (GEM) is a protocol for storing optical quantum states of light in atomic ensembles. The primary motivation for such a technology is that quantum key distribution (QKD), which uses Heisenberg uncertainty to guarantee security of cryptographic keys, is limited in transmission distance. The development of a quantum repeater is a possible path to extend QKD range, but a repeater will need a quantum memory. In our experiments we use a gas of rubidium 87 vapor that is contained in a warm gas cell. This makes the scheme particularly simple. It is also a highly versatile scheme that enables in-memory refinement of the stored state, such as frequency shifting and bandwidth manipulation. The basis of the GEM protocol is to absorb the light into an ensemble of atoms that has been prepared in a magnetic field gradient. The reversal of this gradient leads to rephasing of the atomic polarization and thus recall of the stored optical state. We will outline how we prepare the atoms and this gradient and also describe some of the pitfalls that need to be avoided, in particular four-wave mixing, which can give rise to optical gain.

The gradient echo memory is a protocol for storing optical quantum states of light in atomic ensembles. Quantum memory is a key element of a quantum repeater, which can extend the range of quantum key distribution. We outline the operation of the scheme when implemented in a 3-level atomic ensemble.

التدرج صدى الذاكرة الكم في الحارة بخار الذرية

Gradient  echo memory (GEM) is a protocol for storing optical quantum states of light in  atomic ensembles. The primary motivation for such a technology ...

Nanofabrication of Gate-defined GaAs/AlGaAs Lateral Quantum Dots

A quantum computer is a computer composed of quantum bits (qubits) that takes advantage of quantum effects, such as superposition of states and entanglement, to solve certain problems exponentially faster than with the best known algorithms on a classical computer. Gate-defined lateral quantum dots on GaAs/AlGaAs are one of many avenues explored for the implementation of a qubit. When properly fabricated, such a device is able to trap a small number of electrons in a certain region of space. The spin states of these electrons can then be used to implement the logical 0 and 1 of the quantum bit. Given the nanometer scale of these quantum dots, cleanroom facilities offering specialized equipment- such as scanning electron microscopes and e-beam evaporators- are required for their fabrication. Great care must be taken throughout the fabrication process to maintain cleanliness of the sample surface and to avoid damaging the fragile gates of the structure. This paper presents the detailed fabrication protocol of gate-defined lateral quantum dots from the wafer to a working device. Characterization methods and representative results are also briefly discussed. Although this paper concentrates on double quantum dots, the fabrication process remains the same for single or triple dots or even arrays of quantum dots. Moreover, the protocol can be adapted to fabricate lateral quantum dots on other substrates, such as Si/SiGe.

This paper presents a detailed fabrication protocol for gate-defined semiconductor lateral quantum dots on gallium arsenide heterostructures. These nanoscale devices are used to trap few electrons for use as quantum bits in quantum information processing or for other mesoscopic experiments such as coherent conductance measurements.

النانوية من بوابة المعرفة الغاليوم / AlGaAs الجانبي نقاط الكم

A quantum computer is a computer composed of quantum bits (qubits) that takes advantage of quantum effects, such as superposition of states and ...

Analysis of Contact Interfaces for Single GaN Nanowire Devices

Single GaN nanowire (NW) devices fabricated on SiO2 can exhibit a strong degradation after annealing due to the occurrence of void formation at the contact/SiO2 interface. This void formation can cause cracking and delamination of the metal film, which can increase the resistance or lead to a complete failure of the NW device. In order to address issues associated with void formation, a technique was developed that removes Ni/Au contact metal films from the substrates to allow for the examination and characterization of the contact/substrate and contact/NW interfaces of single GaN NW devices. This procedure determines the degree of adhesion of the contact films to the substrate and NWs and allows for the characterization of the morphology and composition of the contact interface with the substrate and nanowires. This technique is also useful for assessing the amount of residual contamination that remains from the NW suspension and from photolithographic processes on the NW-SiO2 surface prior to metal deposition. The detailed steps of this procedure are presented for the removal of annealed Ni/Au contacts to Mg-doped GaN NWs on a SiO2 substrate.

A technique was developed that removes Ni/Au contact metal films from their substrate to allow for the examination and characterization of the contact/substrate and contact/NW interfaces of single GaN nanowire devices.

تحليل الاتصال واجهات لأجهزة أسلاك متناهية الصغر واحدة الجاليوم

Single GaN nanowire (NW) devices fabricated on SiO2 can exhibit  a strong degradation after annealing due to the  occurrence of void formation at the ...

Construction and Characterization of External Cavity Diode Lasers for Atomic Physics

Since their development in the late 1980s, cheap, reliable external cavity diode lasers (ECDLs) have replaced complex and expensive traditional dye and Titanium Sapphire lasers as the workhorse laser of atomic physics labs1,2. Their versatility and prolific use throughout atomic physics in applications such as absorption spectroscopy and laser cooling1,2 makes it imperative for incoming students to gain a firm practical understanding of these lasers. This publication builds upon the seminal work by Wieman3, updating components, and providing a video tutorial. The setup, frequency locking and performance characterization of an ECDL will be described. Discussion of component selection and proper mounting of both diodes and gratings, the factors affecting mode selection within the cavity, proper alignment for optimal external feedback, optics setup for coarse and fine frequency sensitive measurements, a brief overview of laser locking techniques, and laser linewidth measurements are included.

This is an instructional paper to guide the construction and diagnostics of external cavity diode lasers (ECDLs), including component selection and optical alignment, as well as the basics of frequency reference spectroscopy and laser linewidth measurements for applications in the field of atomic physics.

البناء وتوصيف الخارجية تجويف ديود ليزر للفيزياء الذرية

Since their development in the late 1980s, cheap, reliable external cavity diode lasers (ECDLs) have replaced complex and expensive traditional dye and ...

Quantum State Engineering of Light with Continuous-wave Optical Parametric Oscillators

Engineering non-classical states of the electromagnetic field is a central quest for quantum optics1,2. Beyond their fundamental significance, such states are indeed the resources for implementing various protocols, ranging from enhanced metrology to quantum communication and computing. A variety of devices can be used to generate non-classical states, such as single emitters, light-matter interfaces or non-linear systems3. We focus here on the use of a continuous-wave optical parametric oscillator3,4. This system is based on a non-linear &#967;2 crystal inserted inside an optical cavity and it is now well-known as a very efficient source of non-classical light, such as single-mode or two-mode squeezed vacuum depending on the crystal phase matching. 
Squeezed vacuum is a Gaussian state as its quadrature distributions follow a Gaussian statistics. However, it has been shown that number of protocols require non-Gaussian states5. Generating directly such states is a difficult task and would require strong &#967;3 non-linearities. Another procedure, probabilistic but heralded, consists in using a measurement-induced non-linearity via a conditional preparation technique operated on Gaussian states. Here, we detail this generation protocol for two non-Gaussian states, the single-photon state and a superposition of coherent states, using two differently phase-matched parametric oscillators as primary resources. This technique enables achievement of a high fidelity with the targeted state and generation of the state in a well-controlled spatiotemporal mode.

We describe the reliable generation of non-Gaussian states of traveling optical fields, including single-photon states and coherent state superpositions, using a conditional preparation method operated on the non-classical light emitted by optical parametric oscillators. Type-I and type-II phase-matched oscillators are considered and common procedures, such as the required frequency filtering or the high-efficiency quantum state characterization by homodyning, are detailed.

الدولة الكم هندسة الضوء مع استمرار موجة حدودي البصرية المذبذبات

Engineering non-classical states of the electromagnetic field is a central quest for quantum optics1,2. Beyond their fundamental significance, such states ...

Investigating Single Molecule Adhesion by Atomic Force Spectroscopy

Atomic force spectroscopy is an ideal tool to study molecules at surfaces and interfaces. An experimental protocol to couple a large variety of single molecules covalently onto an AFM tip is presented. At the same time the AFM tip is passivated to prevent unspecific interactions between the tip and the substrate, which is a prerequisite to study single molecules attached to the AFM tip. Analyses to determine the adhesion force, the adhesion length, and the free energy of these molecules on solid surfaces and bio-interfaces are shortly presented and external references for further reading are provided. Example molecules are the poly(amino acid) polytyrosine, the graft polymer PI-g-PS and the phospholipid POPE (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine). These molecules are desorbed from different surfaces like CH3-SAMs, hydrogen terminated diamond and supported lipid bilayers under various solvent conditions. Finally, the advantages of force spectroscopic single molecule experiments are discussed including means to decide if truly a single molecule has been studied in the experiment.

A protocol to couple a large variety of single molecules covalently onto an AFM tip is presented. Procedures and examples to determine the adhesion force and free energy of these molecules on solid supports and bio-interfaces are provided.

التحقيق احدة جزيء التصاق بواسطة القوة الذرية الطيفي

Atomic force spectroscopy is an ideal tool to study molecules at surfaces and interfaces. An experimental protocol to couple a large variety of single ...

Selective Area Modification of Silicon Surface Wettability by Pulsed UV Laser Irradiation in Liquid Environment

The wettability of silicon (Si) is one of the important parameters in the technology of surface functionalization of this material and fabrication of biosensing devices. We report on a protocol of using KrF and ArF lasers irradiating Si (001) samples immersed in a liquid environment with low number of pulses and operating at moderately low pulse fluences to induce Si wettability modification. Wafers immersed for up to 4 hr in a 0.01% H2O2/H2O solution did not show measurable change in their initial contact angle (CA) ~75&#176;. However, the 500-pulse KrF and ArF lasers irradiation of such wafers in a microchamber filled with 0.01% H2O2/H2O solution at 250 and 65 mJ/cm2, respectively, has decreased the CA to near 15&#176;, indicating the formation of a superhydrophilic surface. The formation of OH-terminated Si (001), with no measurable change of the wafer&#8217;s surface morphology, has been confirmed by X-ray photoelectron spectroscopy and atomic force microscopy measurements. The selective area irradiated samples were then immersed in a biotin-conjugated fluorescein-stained nanospheres solution for 2 hr, resulting in a successful immobilization of the nanospheres in the non-irradiated area. This illustrates the potential of&#160;the method for selective area biofunctionalization and fabrication of advanced Si-based biosensing architectures. We also describe a similar protocol of irradiation of wafers immersed in methanol (CH3OH) using ArF laser operating at pulse fluence of 65 mJ/cm2 and in situ formation of a strongly hydrophobic surface of Si (001) with the CA of 103&#176;. The XPS results indicate ArF laser induced formation of Si&#8211;(OCH3)x compounds responsible for the observed hydrophobicity. However, no such compounds were found by XPS on the Si surface irradiated by KrF laser in methanol, demonstrating the inability of the KrF laser to photodissociate methanol and create -OCH3 radicals.

We report on a process of in situ alteration of HF treated Si (001) surface into a hydrophilic or hydrophobic state by irradiating samples in microfluidic chambers filled with&#160;H2O2/H2O solution (0.01%-0.5%) or methanol solutions using pulsed UV laser of a relative low pulse fluence.

انتقائية المساحة تعديل السيليكون بلل السطح بواسطة الليزر النبضي للأشعة فوق البنفسجية تشعيع في البيئة السائلة

The wettability of silicon (Si) is one of the important parameters in the technology of surface functionalization of this material and fabrication of ...

Silicon Metal-oxide-semiconductor Quantum Dots for Single-electron Pumping

As mass-produced silicon transistors have reached the nano-scale, their behavior and performances are increasingly affected, and often deteriorated, by quantum mechanical effects such as tunneling through single dopants, scattering via interface defects, and discrete trap charge states. However, progress in silicon technology has shown that these phenomena can be harnessed and exploited for a new class of quantum-based electronics. Among others, multi-layer-gated silicon metal-oxide-semiconductor (MOS) technology can be used to control single charge or spin confined in electrostatically-defined quantum dots (QD). These QD-based devices are an excellent platform for quantum computing applications and, recently, it has been demonstrated that they can also be used as single-electron pumps, which are accurate sources of quantized current for metrological purposes. Here, we discuss in detail the fabrication protocol for silicon MOS QDs which is relevant to both quantum computing and quantum metrology applications. Moreover, we describe characterization methods to test the integrity of the devices after fabrication. Finally, we give a brief description of the measurement set-up used for charge pumping experiments and show representative results of electric current quantization.

The fabrication process and experimental characterization techniques relevant to single-electron pumps based on silicon metal-oxide-semiconductor quantum dots are discussed.

السيليكون المعدنية أكسيد أشباه الموصلات الكم النقاط لالضخ وحيد الإلكترون

As mass-produced silicon transistors have reached the nano-scale, their behavior and performances are increasingly affected, and often deteriorated, by ...

Use of a Multi-compartment Dynamic Single Enzyme Phantom for Studies of Hyperpolarized Magnetic Resonance Agents

Imaging of hyperpolarized substrates by magnetic resonance shows great clinical promise for assessment of critical biochemical processes in real time. Due to fundamental constraints imposed by the hyperpolarized state, exotic imaging and reconstruction techniques are commonly used. A practical system for characterization of dynamic, multi-spectral imaging methods is critically needed. Such a system must reproducibly recapitulate the relevant chemical dynamics of normal and pathological tissues. The most widely utilized substrate to date is hyperpolarized [1-13C]-pyruvate for assessment of cancer metabolism. We describe an enzyme-based phantom system that mediates the conversion of pyruvate to lactate. The reaction is initiated by injection of the hyperpolarized agent into multiple chambers within the phantom, each of which contains varying concentrations of reagents that control the reaction rate. Multiple compartments are necessary to ensure that imaging sequences faithfully capture the spatial and metabolic heterogeneity of tissue. This system will aid the development and validation of advanced imaging strategies by providing chemical dynamics that are not available from conventional phantoms, as well as control and reproducibility that is not possible in vivo.

A multi-compartment dynamic phantom is used to simulate some biology of interest for metabolic studies using hyperpolarized magnet resonance agents.

استخدام متعدد مقصورة الحيوي واحدة أنزيم فانتوم للدراسات وكلاء الرنين المغناطيسي Hyperpolarized

Imaging of hyperpolarized substrates by magnetic resonance shows great clinical promise for assessment of critical biochemical processes in real time. Due ...

Compact Lens-less Digital Holographic Microscope for MEMS Inspection and Characterization

A micro-electro-mechanical-system (MEMS) is a widely used component in many industries, including energy, biotechnology, medical, communications, and automotive. However, effective inspection and characterization metrology systems are needed to ensure the functional reliability of MEMS. This study presents a system based on digital holography as a tool for MEMS metrology. Digital holography has gained increasing attention in the past 20 years. With the fast development and decreasing cost of sensor arrays, resolution of such systems has increased broadening potential applications. Thus, it has attracted attention from both research and industry sides as a potential reliable tool for industrial metrology. Indeed, by recording the interference pattern between an object beam (which contains sample height information) and a reference beam on a CCD camera, one can retrieve the quantitative phase information of an object. However, most of digital holographic systems are bulky and thus not easy to implement on industry production lines. The novelty of the system presented is that it is lens-less and thus very compact. In this study, it is shown that the Compact Digital Holographic Microscope (CDHM) can be used to evaluate several characteristics typically consider as criteria in MEMS inspections. The surface profiles of MEMS in both static and dynamic conditions are presented. Comparison with AFM is investigated to validate the accuracy of the CDHM.

We present a compact reflection digital holographic system (CDHM) for inspection and characterization of MEMS devices. A lens-less design using a diverging input wave providing natural geometrical magnification is demonstrated. Both static and dynamic studies are presented.

المدمجة عدسة أقل الرقمي المجسم مجهر لفحص ممس وتوصيف

A micro-electro-mechanical-system (MEMS) is a widely used component in many industries, including energy, biotechnology, medical, communications, and ...